Source : Webster's Revised Unabridged Dictionary (1913)

Leash \Leash\, n. [OE. lese, lees, leece, OF. lesse, F. laisse,
   LL. laxa, fr. L. laxus loose. See {Lax}.]
   1. A thong of leather, or a long cord, by which a falconer
      holds his hawk, or a courser his dog.

            Even like a fawning greyhound in the leash. --Shak.

   2. (Sporting) A brace and a half; a tierce; three; three
      creatures of any kind, especially greyhounds, foxes,
      bucks, and hares; hence, the number three in general.

            [I] kept my chamber a leash of days.  --B. Jonson.

            Then were I wealthier than a leash of kings.
                                                  --Tennyson.

   3. (Weaving) A string with a loop at the end for lifting warp
      threads, in a loom.

Leash \Leash\, v. t. [imp. & p. p. {Leashed}; p. pr. & vb. n.
   {Leashing}.]
   To tie together, or hold, with a leash.

Source : WordNet®

leash
     n 1: restraint consisting of a rope (or light chain) used to
          restrain an animal [syn: {tether}, {lead}]
     2: the cardinal number that is the sum of one and one and one
        [syn: {three}, {3}, {III}, {trio}, {threesome}, {tierce},
        {troika}, {triad}, {trine}, {trinity}, {ternary}, {ternion},
         {triplet}, {tercet}, {terzetto}, {trey}, {deuce-ace}]
     3: a figurative restraint; "asked for a collar on program
        trading in the stock market"; "kept a tight leash on his
        emotions"; "he's always gotten a long leash" [syn: {collar}]
     v : fasten with a rope; "rope the bag securely" [syn: {rope}]